Conventional load balancers are typically single, dedicated boxes that include multiple network interface controllers (NICs), for example eight NICs, with some of the NICs handling inbound traffic from/outbound traffic to clients and the other NICs handling outbound traffic from/inbound traffic to the host devices (e.g., servers such as web servers) that are being load balanced. Bandwidth or throughput on these conventional load balancers is typically in the range of 40 Gigabits per second (Gbps) on the client side and 40 Gbps on the server side. As the scale and scope of network-based applications and network-based services such as cloud computing services have increased, data centers may house hundreds or even thousands of host devices (e.g., web servers) that need to be load balanced. Conventional load balancers may not scale well in such environments.
Further, conventional load balancers typically use techniques such as max connections (or max conns), round robin, and/or least connections (least conns) applied to data collected from the host devices to select which host device will handle a connection. In addition, conventional load balancers typically serve as proxies to the host devices that they front and thus terminate connections (e.g., Transmission Control Protocol (TCP) connections) from the clients and send the client traffic to the host devices on TCP connections established between the host devices and the load balancer. Thus, a host device and a client do not communicate over a direct TCP connection when using these conventional load balancers.
While embodiments are described herein by way of example for several embodiments and illustrative drawings, those skilled in the art will recognize that embodiments are not limited to the embodiments or drawings described. It should be understood, that the drawings and detailed description thereto are not intended to limit embodiments to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include”, “including”, and “includes” mean including, but not limited to.